I recently had a light bulb burn out and curiosity got the best of me. When faced with the many options of light bulbs, various wattage, and styles of bulbs one can go crazy considering all the options.

Do the savings on the compact florescent bulbs really save you money? Lets look at the numbers.

Using Amazon as a baseline for product pricing, you can get 4 100 Watt GE Bulbs for $8.00 (approx 2$ per bulb) and a Sylvania compact florescent for 9.99 (23 Watt). Avista rates are .07883 per kWh and Inland Power’s rates at .0575 per kWH.

Lets look at the 100 Watt Bulb. For the sake of this calculation, lets assume this bulb is an exterior light that runs 12 hours a day from 5:00 PM to 5:00 AM.

The 100 Watt bulb costs $2.14 per month on Inland Power and $2.93 per month on Avista.

In comparison, the 23 Watt Bulb costs: $0.49 per month on Inland Power and $0.67 per month on Avista.

How does this savings in cost justify paying 5x more for the bulb?

With Inland Power the savings per month is $1.65 per month and Avista’s savings is $2.26 per month. When we net out the real difference between the two bulbs ($9.99 – $2.00 = $7.99); your break even point on Inland Power is just under 5 months whereas your break even on Avista is 3.5 months, after which you realize a $1.00-$2.00 positive savings on each 100 Watt bulb you replace (assuming a 12 hour run time average).

The savings comes down to how much your power costs and how often you use the light. If the light is used more than 10 hours per day, such as an exterior light, kitchen or security light, the cost / reward ratio is there, but on lesser used lights a lower wattage bulb would probably suffice.